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Filling small tanks

Now I have to figure out what size gas bottles to get. Maybe get the large rental to keep in the shop.

The largest purchase size is the 160 at my LWS.

The 160 is still kind of heavy so thinking for my truck I'll get the 80. Should get close to 4 hours out of it and I need to save space and weight.

There has got to be a way to refill the small tank from the large (225 I think) tank. I saw a post about it somewhere online but lost it. I would like to have that option with such a small tank or I may need to rethink for a 160 portable.

how much welding will you be doing, if quite a bit, get the rental, refills are much cheaper, as far as a set up to fill your own tanks, i have no idea about buying one, making one would be easy if you had the plumbing connectors

Do not do this with acetylene!!Do not do this with any flammable gas either!!

Even other gases can be dangerous. High pressure, suffocation from oxygen displacement, bottle turned into a missle, explosion, etc.

Get two appropriate cgaxxx nuts & nipples + a 3000# tee + a gauge. Do not use a rubber hose, just the fittings. Tighten it all up then open empty bottle valve all the way then crack open the full bottle a tiny bit & let it fill slowly. If you fill it to fast it will create a lot of heat. Close all valves & crack open a nut to release pressure then remove. The bottles will equalize in pressure so your not actually filling the smaller one all the way.

Do not do this with acetylene!!Do not do this with any flammable gas either!!

Fittings

Western makes the fittings. Your local welding supply should be able to get them, they are replacement nipples that attachs your regulator to bottle. I have been fill my small bottles for years with no problem. Just cannot fill acelylene.

Cylinder and refill prices are all over the map, so a recommendation from Texas may not help someone out of state. I used to like the 220' cylinders, but old age has decided for me that 125' is plenty large. I still have an 80' that I am going to swap in toward a 122'.

Acetylene gets very unstable (explosive) above 15 psi if not in a controlled environment (like inside an acetylene tank filled with I believe it's acetone). I was always told the acetone absorbs the acetylene to keep the molecules from bouncing off each other & exploding. This is why your low side gauge has a big red area after 15#. If you tried refilling from tank to tank you would fill your new tank with only acetylene gas & have a very unstable bottle although you might not even get it filled before it went boom.

Feel free to correct me if I'm wrong here. Here is a copy & paste.

Pure acetylene is a colourless gas with a pleasant odour; as prepared from calcium carbide it usually contains traces of phosphine that cause an unpleasant garliclike odour. Acetylene can be decomposed to its elements with the liberation of heat. The decomposition may or may not give rise to explosions, depending on conditions. Pure acetylene under pressure in excess of about 15 pounds per square inch or in liquid or solid form explodes with extreme violence.

Pure acetylene is a colourless gas with a pleasant odour; as prepared from calcium carbide it usually contains traces of phosphine that cause an unpleasant garliclike odour. Acetylene can be decomposed to its elements with the liberation of heat. The decomposition may or may not give rise to explosions, depending on conditions. Pure acetylene under pressure in excess of about 15 pounds per square inch or in liquid or solid form explodes with extreme violence.

And this is why you need to stand up a bottle for the same time as the bottle was laid down for transport. It allows time for the acetone and other goodies to settle properly through the charcoal.

ACETYLENE CYLINDERS.—Acetylene stored in a free state under pressure greater than 15 psi can be made to break down by heat or shock and possibly explode. Under pressure of 29.4 psi, acetylene becomes self-explosive, and a slight shock will cause it to explode spontaneously. However, when dissolved in acetone, it Figure 15-27.—Acetylene cylinder. can be compressed into cylinders at pressures up to 250 psi. The acetylene cylinder (fig. 15-27) is filled with porous materials, such as balsa wood, charcoal, and shredded asbestos, to decrease the size of the open spaces in the cylinder. Acetone, a colorless, flammable liquid, is added until about 40 percent of the porous material is filled. The filler acts as a large sponge to absorb the acetone, which, in turn, absorbs the acetylene. In this process, the volume of the acetone increases as it absorbs the acetylene, while acetylene, being a gas, decreases in volume. The acetylene cylinders are equipped with safety plugs, which have a small hole through the center. This hole is filled with a metal alloy, which melts at approximately 212°F or releases at 500 psi. When a cylinder is overheated, the plug will melt and permit the acetylene to escape before a dangerous pressure can build up. The plug hole is too small to permit a flame to burn back into the cylinder if the escaping acetylene should become ignited.